Lifting and material handling apparatus

ABSTRACT

The invention relates to a lifting apparatus which can be used to handle, for example, containers, steel ingots, packages, logs, pulp, steel sheets, and so forth. It consists of a lifting arrangement, a hinge block, and lower lifting arms pivotably connected at either end of the hinge block. Adjustable tie rods connect a respective side of the lifting arrangement to a respective lower lifting arm. A lifting rod extends through both the hinge block and the lifting arrangement, and is movable relative to the upper lifting arm, and movable downward relative to the hinge block. A collar on the rod engages the bottom of the hinge block so that the hinge block moves upwardly with the lifting rod when the collar is in contact with the hinge block. A hydraulic cylinder has the top end of its piston connected to the upper lifting arm, and the bottom end of its fluid cylinder connected to the bottom end of the lifting rod, and a valve is included in the line between the hydraulic fluid reservoir and the fluid cylinder. The valve controls relative movement of the hinge block and the lifting rod to thereby control relative movement of the hinge block and the upper arm under the action of gravity and a hoisting means. The apparatus is adaptable to semi-automatic, automatic or remote control operation. In one of the embodiments, the lifting arrangement consists of an upper lifting arm which is disposed above the hinge block and extends laterally thereof. In a second embodiment, the lifting arrangement comprises vertically extending bars which are disposed on either side of the hinge block and which are attached to each other at both ends thereof.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a novel lifting and material handlingapparatus. More specifically, this invention relates to such apparatuswhich can be adapted to either semi-automatic, automatic or remotecontrol operation.

2. Statement of the Prior Art

The prior art teaches many lifting and material handling apparatus, forexample sheet lifting apparatus, as shown in U.S.A. Pat. Nos. 2,375,747,Brown, May 15, 1945; 2,732,248, Jaeger, Jan. 24, 1956; 3,044,819,Pierre, July 17, 1962; 3,198,568, Mindrum, Aug. 3, 1965; 3,854,766, Dec.17, 1974, Jordan and 3,796,332, Kawamura, Mar. 12, 1974. Basically, theapparatus of the prior art consist of three types: The first is the lowheadroom type which uses a rack and pinion drive to close the graspinglegs thereof. This type does not have a very powerful gripping actionand can therefore be unsafe.

The second and third types use the tong principle and consist of theparallelogram type and the adjustable angle type.

The adjustable angle type has the disadvantage of requiring frequentadjustment of angles, and if the operator is careless, and does notcorrectly adjust the angles, safety is compromised.

Both the parallelogram type and the adjustable angle type require a handwheel operated mechanism to open and close the legs. This mechanismrequires a high ratio gear box, mechanical load brake and variouslinkages etc. All this apparatus is very costly and increases the deadweight of the unit. Furthermore, the operation of the hand wheel is timeconsuming and requires a good deal of physical effort.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a lifting andmaterial handling apparatus which overcomes the disadvantages of knownapparatus.

It is a more specific object of the invention to provide apparatus whichfeatures greater safety.

It is a still more specific object of the invention to provide apparatuswhich is adaptable to semiautomatic, automatic or remote controloperation.

In accordance with the invention, a lifting apparatus, comprising: ahinge block; two lower arms extending from respective sides of the hingeblock, each lower arm being pivotably attached to its respective side ofthe hinge block; an opening arrangement; means connecting said openingarrangement to each of said lower arms; a lifting rod for moving thehinge block relative to the opening arrangement; and means forconnecting the lifting rod to either the hinge block or the openingarrangement thereby controlling the closing or opening of the liftingarms respectively under the action of gravity and a hoisting means.

In one embodiment, the opening arrangement comprises an upper openingarm disposed above said hinge block and extending laterally thereof.

In a second embodiment, said opening arrangement comprises verticallyextending bars disposed on either side of said hinge block and connectedto each other at the top and bottom ends thereof.

The lifting rod may extend through both said hinge block and saidlifting arrangement, said opening rod being movable relative to saidopening arrangement and movable relative to said hinge block; and meanson said lifting rod for engaging the bottom of said hinge block;whereby, when said means for engaging contacts the bottom of said hingeblock, said hinge block will move upwardly with said lifting rod.

The means for connecting the lifting rod may comprise a hydrauliccylinder having a piston slidably disposed in a fluid cylinder; the topend of said piston being fixed to said upper lifting arm; the bottom endof said fluid cylinder being fixed to the bottom end of said liftingrod.

The means connecting may comprise two adjustable tie rods, each tie rodbeing pivotably connected, at one end thereof, to a respective side ofthe upper lifting arm, and, at the other end thereof, to a respectivelower lifting arm.

The apparatus may further comprise a hydraulic fluid reservoir; meansconnecting said fluid reservoir with said fluid cylinder; and valvemeans in said means connecting said fluid reservoir with said fluidcylinder to permit or prevent hydraulic fluid from flowing between saidfluid cylinder and said reservoir.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by an examination of thefollowing description, together with the accompanying drawings, inwhich:

FIG. 1 illustrates one embodiment of the apparatus in its transportposition;

FIG. 1A is a section through A--A of FIG. 1;

FIG. 1B is a section through B--B of FIG. 1;

FIG. 2 illustrates the apparatus of FIG. 1 in its load grippingposition;

FIG. 3 illustrates the apparatus of FIG. 1 in its load release position;

FIG. 4 is a hydraulic circuit diagram of the hydraulic valves;

FIG. 5 illustrates a second embodiment of the apparatus in its transportposition; and

FIG. 6 is a side view of FIG. 5.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, the apparatus in accordance with the inventioncomprises a hinge block 1 having lower arms 3 and 5 pivotably attachedat respective sides thereof. Load grasping means, such as lifting legs 7and 9, are pivotably attached to the respective free ends of the lowerarms. In this particular embodiment, the arms 3 and 5 consist,respectively, of two slat-like members 3a, 3b, and 5a, 5b. It will, ofcourse, be appreciated that other forms for these arms are possible.

A lifting rod 11 extends through the hinge block 1 so as to be movablerelative to the hinge block, as will be discussed below, and terminates,at its top end, in an attachment ring 13. The ring can be connected to,for example, the hook of a crane, as shown in dotted lines in FIGS. 1, 2and 3 and as well known in the art. The bottom end of the lifting rodincludes a fixed collar 15, in physical engagement with the bottom ofthe hinge block, whereby, when the lifting rod is moved upwardly, andthe collar contacts the hinge block, the hinge block will move with it.

Disposed above the hinge block is an arrangement for opening the liftingarms, in this embodiment, laterally extending upper bar 17, having acollar 19 disposed centrally thereof. The lifting rod 11 extends throughthe collar 19, and is movable relative to the collar 19. Extending fromeither side of the bar 17 are arm tie rods 21 and 23, the tie rods beingpivotably attached, at one end thereof, to the respective sides of theupper bar, each tie rod being pivotably attached, at the other endsthereof, to a respective lower arm.

Also extending through the hinge block are hydraulic cylinders 25 and27. Hydraulic cylinder 25 includes piston 25p, whose top end is attachedto the upper bar 17, and fluid cylinder 25c, whose lower end is attachedto the lower end of the lifting rod 11. As the cylinder 25 is notattached to the hinge block, it is movable relative to the hinge block.Hydraulic cylinder 27 similarly includes piston 27p, which is alsoattached, at the top end thereof, to the upper bar 17, and fluidcylinder 27c, which is attached, at the lower end thereof and throughmember 29, to the bottom of the hinge block.

As can be seen in FIG. 4, hydraulic cylinder 25 is controlled by ON/OFFand speed control valve 26 (also seen in FIG. 1) while hydraulic valve27 is controlled by speed control valve 28. Hydraulic cylinder 27 is nota necessary part of the apparatus in accordance with the invention, butis included in a preferred embodiment of the invention to control thespeed of the leg movement as will be discussed below.

To better understand the construction of the hinge block in accordancewith the illustrated embodiment, attention is directed to FIGS. 1A and1B. As can be seen in these Figures, the hinge block comprises plates 31and 33. Disposed between the plates is a block 35 having a cylindricalopening 37 for receiving lifting rod 11. The diameter of 37 is, ofcourse, greater than the diameter of the lifting rod. It will, ofcourse, be appreciated that this is only one construction of the hingeblock, and there are many other alternatives for example a solid blockwith three openings to receive, respectively, the rod 11 and thecylinders 25 and 27, all of which are within the knowledge of oneskilled in the art.

Tie rods 21 and 23 are adjustable to adjust the opening and closingextents of the arms 3 and 5. However, they are fixed in length duringthe operation of the apparatus.

In operation, the apparatus works as follows:

With the apparatus suspended from a hoist by ring 13 and the pistons 25and 27 in their fully extended position, and valve 26 closed, the arms 3and 5 are in the fully open position as shown in FIG. 1. Under theaction of gravity, hinge block 1 will remain in the fully down positionso that lower arms 3 and 5 will remain fixed in their fully openposition. When a lifting force is applied at 13, it will be transmitted,through rod 11, to collar 15. Thus, the lifting force will be applied tothe bottom of hinge block 1 which will move upward carrying with it theremainder of the apparatus.

The apparatus is so carried till it is over the load to be lifted, andit is then lowered over the load. The valve 26 is then opened, so thathydraulic fluid is free to flow out of fluid cylinder 25c. The weight ofarms 3 and 5 and legs 7 and 9 and upper bar 17 and tie rods 21 and 23will cause the free ends of the arms 3 and 5 to move downwardly, so thatlegs 7 and 9 move towards each other. This motion will continue untilthe legs grasp the bottom of the load to be lifted 39 as shown in FIG.2. The load can now be hoisted, and it will remain secure in the graspof the legs due to the force of gravity alone. It is especially notedthat valve 26 can remain open during hoisting. It will be seen that thenatural force of gravity prevents the arms 3 and 5 from opening tothereby provide the required safety feature without the necessity of amanual or mechanical safety step which could easily be forgotten.

To release the load, the apparatus is lowered so that the load rests onthe skids 41 shown in FIG. 3 and the pads 43 of the grasping means reston the top of the load, or the bottoms 45 of the grasping means rest ona surface. Further lowering of the crane hook (shown in dotted lines),will force the lifting rod 11 downwardly. As the bottom end of fluidcylinder 25c is attached to the bottom end of lifting rod 11, thecylinder 25c will follow the motion of 11, and hydraulic fluid will bedrawn into the cylinder as the valve 26 is open. The valve 26 is closedwhen the lifting rod has moved downward a sufficient amount, and closingthe valve will lock the lifting rod with the upper bar 17. This is thesituation as illustrated in FIG. 3.

We will now consider the operation of the apparatus when the crane hookis lifted. In the first instance, we will consider the operation of theapparatus without hydraulic cylinder 27 in the circuit.

When the crane hook is lifted, pads 43 will be lifted off the load orbottoms 45 will be lifted off the ground. By action of gravity, thehinge block 1 will begin to fall downward, thus spreading legs 3 and 5apart and away from each other until they take up the position as shownin FIG. 1. It can thus be seen that hydraulic cylinder 27 is notessential for the operation of the invention and could be considered aninventive improvement of the invention herein.

With hydraulic cylinder 27 in the system, and considering the circuitdiagram of FIG. 4, it can be seen that hydraulic cylinder 27 controlsthe rate at which the hinge block 1 moves downwardly. More accurately,the rate at which the hinge block moves downwardly is determined by therate at which control valve 28 permits hydraulic fluid to be withdrawnfrom the top of cylinder 27c.

Referring now to FIGS. 5 and 6, like references in these Figures referto the same parts as referred to in FIGS. 1 to 4. As can be seen, theembodiments in FIGS. 5 and 6 are identical to the embodiments in FIGS. 1to 4 except that, instead of having the arrangement for opening thelifting arms comprising a laterally extending upper opening bar 17, inthe FIGS. 5 and 6 embodiments, the arrangement for opening the liftingarms comprises vertically extending bars 17a and 17b. The bars 17a and17b extend on either side of the hinge 1 and are centrally located. Thebars are connected to the collar 19 by means 101a and 101b at the topends of 17a and 17b respectively, and the bottom ends of 17a and 17b areconnected to each other by means 103. The arm tie rods 21 and 23 areonce again connected, respectively, to arms 3 and 5, however, in thisembodiment, the tie rods 21 and 23 are connected to the bottoms of thearms 5 and 7 instead of the tops. The other ends of the tie rods areconnected to means 102. Thus, once again, the tie rods will be movedtogether with the arrangement for raising and lifting the arms, namely,the bars 17a and 17b. As will be obvious, the arms 17a and 17b will bemoved together.

As also seen in FIGS. 5 and 6, the apparatus in this embodiment includestwo pairs of rollers 103 disposed on either sides of FIG. 17b, and twopairs of rollers 105 disposed on either side of bar 17a. These are guiderollers which equalize the opening angle of the arms as they guide thebars 17a and 17b in a straight path.

The operation of the FIGS. 5 and 6 embodiments is identical to theoperation of the previous embodiment as above described except that,when the bars 17a and 17b are moved upwardly, then the arms 3 and 5 arepushed upwardly instead of being pulled upwardly. In all other respects,the operation of the second embodiment is identical to the operation ofthe first embodiment.

The apparatus may be converted for fully automatic operation by theaddition of a valve actuator for, or in place of, valve 26. The actuatorwould sense suitable positions of the lifting cycle and open and closeautomatically in response to the respective stimulus.

Remote operation of the apparatus would be made possible by use of asolenoid valve or a radio controlled valve actuator for, or in place of,valve 26. Remote control of valves is well known in the art so thatfurther description of such a conversion facility is not necessary.

As above noted, the apparatus is absolutely fail-safe in operation sincethe weight of the lifted load causes a powerful gripping action of thelegs based on the tong principle. Once the load is lifted, and firmlygripped by the lifting legs 7 and 9, operation of valve 26 has noeffect. Thus, it is impossible to release the load without firstlowering it onto a rest so that the weight of the load is taken off thecrane.

Although one embodiment has been above-described, this was for thepurpose of describing, but not limiting, the invention. Variousmodifications, which will come readily to the mind of one skilled in theart, are within the scope of the invention as defined in the appendedclaims.

I claim:
 1. A lifting apparatus comprising:a hinge block; two lower armsextending from respective sides of the hinge block, each lower arm beingpivotably connected to its respective side of the hinge block; anopening arrangement including two rod-like means, each rod-like meansbeing pivotably connected to a different one of said lower arms andarranged to either uniformly lift said lower arms, whereby to open saidlower arms, or to lower said lower arms, whereby to close said lowerarms; a lifting rod having an attachment ring at the top end thereof,said lifting rod extending through both said opening arrangement andsaid hinge block; means for connecting having three connectingpositions, said means for connecting, in said first connecting position,connecting said lifting rod to said opening arrangement and, in saidsecond connecting position, connecting said lifting rod to said hingeblock, and, in the third connecting position, connecting both said hingeblock and said opening arrangement to said lifting rod; wherein, whensaid means for connecting is in said first position, said lower armswill open upon application of an upward force at said attachment ringdue only to the action of gravity on said hinge block; and wherein, whensaid means for connecting is in said second position, said lower armswill close due only to the action of gravity on said lower arms; andwherein, when said means for connecting is in said third position, andsaid lower arms are open, said lower arms will remain open.
 2. Apparatusas defined in claim 1 wherein said lifting rod extends through both saidhinge block and said lifting arrangement, said opening rod being movablerelative to said opening arrangement and movable relative to said hingeblock; andmeans on said lifting rod for engaging the bottom of saidhinge block; whereby, when said means for engaging contacts the bottomof said hinge block, said hinge block will move upwardly with saidlifting rod.
 3. Apparatus as defined in claim 2 wherein said means forconnecting comprises a hydraulic cylinder having a piston slidablydisposed in a fluid cylinder;the top end of said piston being fixed tosaid opening arrangement: the bottom end of said fluid cylinder beingfixed to the bottom end of said lifting rod.
 4. Apparatus as defined inclaim 1 wherein said means for connecting comprises two adjustable tierods, each tie rod being pivotably connected, at one end thereof, to arespective side of the opening arrangement, and, at the other endthereof, to a respective lower lifting arm.
 5. Apparatus as defined inclaim 1 and further comprising lifting legs disposed at the free ends ofsaid lower arms.
 6. Apparatus as defined in claim 3 and comprising ahydraulic fluid reservoir;means connecting said fluid reservoir withsaid fluid cylinder; and valve means in said means connecting said fluidreservoir with said fluid cylinder to permit or prevent hydraulic fluidfrom flowing between said fluid cylinder and said reservoir, and alsocontrol rate of flow.
 7. Apparatus as defined in claim 3 and furthercomprising a second hydraulic cylinder having a piston and fluidcylinder;the top end of the piston of said second hydraulic cylinderbeing fixed to said upper lifting arm; the bottom end of said fluidcylinder of said second hydraulic cylinder being fixed to the bottom ofsaid hinge block; the speed of movement of said piston of said secondhydraulic cylinder into the fluid cylinder of said second hydrauliccylinder being controlled by a speed control valve.
 8. Apparatus asdefined in claim 6 including valve actuator means for automaticallyactuating said valve means under predetermined conditions;whereby saidapparatus operates fully automatically.
 9. Apparatus as defined in claim6 wherein said valve means is remotely controllable;whereby saidapparatus is remotely controllable.
 10. Apparatus as defined in claim 3wherein said opening arrangement comprises an elongated upper openingarm;said upper opening arm being disposed above said hinge block andextending laterally thereof.
 11. Apparatus as defined in claim 10wherein said rod-like means comprises tie rods pivotally connected ateach end of said upper opening arm, a respective tie rod being connectedto a respective lower arm.
 12. Apparatus as defined in claim 3 whereinsaid lifting arrangement comprises vertically extending bars disposed oneither side of said hinge block;said vertically extending bars beingconnected, at the top end thereof, to the top end of said piston; saidvertically extending bars being connected, at the bottom ends thereof,to two adjustable tie rods, each of said tie rods being pivotablyconnected, at the free ends thereof, to a respective lower lifting arm.